Junk I've been like that when in the house alone since I was younger. I also won't go outside in the dark without someone with me, and I'm 27! I'm only now sleeping without music playing to cover up sounds. When I hear a plane pass over I get this sinking feeling in my stomach of pure dread. I remember waking up one morning and there was a chainsaw going off in one of the nearby fields, I just had flashes of leatherface in my head, I was freaking out!!!
I think these kinds of thoughts can just be ingrained in your personality if it's not new for you. If it's new to you and you're usually fine then it'd be something to mention.